Lecture 14 10/23/24 Flashcards
What are the characteristics of Rhodococcus equi?
-gram-pos pleomorphic rods
-Chinese character formations
-facultative intracellular pathogen
-soil organism
-harbored in intestinal tract of adult herbivores
-inhaled or ingested
-seen in 1-6 month old foals
-insidious disease (gradual)
What are the clinical manifestations of Rhodococcus equi?
-chronic suppurative pneumonia
-anorexia
-lethargy
-fever
-nasal discharge +/- cough
-tachypnea
-dyspnea
-nostril flaring
-abdominal breathing
What are the extra-pulmonary manifestations of Rhodococcus equi?
*intestinal manifestations:
-possibly subclinical
-ulcerative colitis
-typhylitis
-suppurative inflammation of colonic/mesenteric lymph nodes
*polysynovitis
*panophthalmitis
*guttural pouch empyema
*sinusitis
*pericarditis
*hepatic and renal abscessation
What findings are seen on bloodwork with Rhodococcus equi?
-hyperfibrinogenemia
-neutrophilic leukocytosis +/- monocytosis
What findings are seen on radiographs with Rhodococcus equi?
-alveolar pattern
-regional consolidation and/or abscessation
Which methods are used to diagnose Rhodococcus equi?
-TTW with cytology and bacterial culture
-PCR
What are the characteristics of antibiotic treatment for Rhodococcus equi?
-erythromycin + rifampin
-given for 4-10 weeks
-can use azithromycin or clarithromycin
What are the side effects of antibiotic treatment of Rhodococcus equi?
-idiosyncratic hyperthermia and tachypnea
-self limiting fecal softening
-Clostridium difficile enterocolitis in mares exposed to the macrolides
What are the supportive treatments for Rhodococcus equi?
-oxygen support
-hyperbaric oxygen
-IV fluids
-nutrition support
-monitoring of fibrinogen
-radiographs/ultrasound for monitoring
What is the prognosis of Rhodococcus equi infection?
-treatment is very successful
-poorer prognosis with extra-pulmonary manifestations of disease
-decreased chance of racing as an adult, but performance in those racing not reduced significantly
What are the surveillance strategies for Rhodococcus equi?
-daily rectal temps
-fibrinogen levels measured every 2 weeks
-WBC count measured every 2 weeks
-ultrasound every 2 weeks (detects peripheral lesions only)
How is Rhodococcus equi controlled?
-avoid high animal density
-avoid sandy/dusty soils and manure laden areas
-pasture rotation
-plant or irrigate dusty paddocks/pastures
-surveillance strategies
-hyperimmune plasma
-prophylactic administration of azithromycin
What are the terms used for moderate/severe and mild equine asthma?
moderate/severe: recurrent airway obstruction/RAO
mild: inflammatory airway disease/IAD
What are the characteristics of equine asthma?
-naturally occurring
-periods of reversible airway inflammation
What causes the clinical signs of equine asthma?
-neutrophil accumulation
-mucus production
-bronchospasm
What is the impact of equine asthma on the lungs?
-decreased compliance
-increased resistance
-increased work of breathing
-arterial hypoxia